Semiautomated Turbidimetric Microbiological Assay for Determination of Cefazolin

Abstract

The Autoturb System, a semiautomated system for photometric bioassay, was used to determine cefazolin content. Suitable conditions for the assay using Streptococcus faecalis ATCC 10541 as the indicator organism included a medium pH of 6.0 to 7.0 and an incubation time of 3 to 3.5 h at 36 C. Multiple independent assays of samples from a common batch showed the test to be highly reproducible. Accuracy of the turbidimetric assay was evaluated by comparing data obtained from a chemical (hydroxylamine) and a biological (disk diffusion) assay. The available data show the turbidimetric assay to be a rapid, accurate, and reproducible method for determining the biological activity of cefazolin samples.

Iodometric and spectrophotometric assays for cephradine after its hydrolysis with a β-lactamase

“…lodometric assays involvin2 alkaline hydrolysis were carried out as described under Methods. Bioassays were carried out by the turbidimetric method (2). Comparison with Bioassay-Since the spectrophotometric method was intended for use in routine assays of cephradine in powders and other formulations, it was compared with the more commonly used bioassay in a series of experiments.…”

“…The method proved to be as accurate as the bioassay in determining the potencies of cephradine bulk formulations used in long-term stability studies, but it has the advantage of being more precise and (2). more rapid to perform than the bioassay.…”

“…Although microbiological assays using agar diffusion (1) or photometric (2) procedures are preferred for the determination of cephalosporins in pharmaceutical preparations, body fluids, and formulations being studied for long-term stability, they are imprecise and tedious.…”

Study of the Efficacy of Real Time-PCR Method for Amikacin Determination Using Microbial Assay

“…However like other bioassays, the microbial assay suffers from significant limitations; these methods are of lower specificity, accuracy and sensitivity. 3,6,7 Some efforts to combat the shortcomings of microbial assay have been reported so far, 8 for example Marengo and coworkers used a special test organism for microbiological assay of amikacin to improve the specificity of the method. They employed a strain of Providencia stuartii which is resistant to multiple antibiotics except amikacin.…”